A conserved dibasic site is essential for correct processing of the peptide hormone AtRALF1 in Arabidopsis thaliana

Matos, Juliana L.; Fiori, Celso S.; Silva-Filho, Marcio C.; Moura, Daniel S.

doi:10.1016/j.febslet.2008.08.025

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Volume 582, Issue 23 , Pages 3343-3347, 15 October 2008

A conserved dibasic site is essential for correct processing of the peptide hormone AtRALF1 in Arabidopsis thaliana

Edited by Michael R. Sussman

Juliana L. Matos
- Departamento de Genética, Escola Superior de Agricultura “Luiz de Queiroz”, Universidade de São Paulo,C.P. 83, 13400-970 Piracicaba, SP, Brazil
Celso S. Fiori
- Departamento de Genética, Escola Superior de Agricultura “Luiz de Queiroz”, Universidade de São Paulo,C.P. 83, 13400-970 Piracicaba, SP, Brazil
Marcio C. Silva-Filho
- Departamento de Genética, Escola Superior de Agricultura “Luiz de Queiroz”, Universidade de São Paulo,C.P. 83, 13400-970 Piracicaba, SP, Brazil
Daniel S. Moura
- Departamento de Genética, Escola Superior de Agricultura “Luiz de Queiroz”, Universidade de São Paulo,C.P. 83, 13400-970 Piracicaba, SP, Brazil
- Departamento de Ciências Biológicas, Escola Paulista de Ciências Biológicas, Universidade Federal de São Paulo, Campus Diadema, 09972-270 Diadema, SP, Brazil
- Corresponding author. Address: Departamento de Ciências Biológicas, Escola Paulista de Ciências Biológicas, Universidade Federal de São Paulo, Campus Diadema, 09972-270 Diadema, SP, Brazil. Fax: +55 11 40436428.

Received 19 July 2008; received in revised form 2 August 2008; accepted 21 August 2008. published online 05 September 2008.

Abstract

Prohormone proteins in animals and yeast are typically processed at dibasic sites by convertases. Propeptide hormones are also found in plants but little is known about processing. We show for the first time that a dibasic site upstream of a plant peptide hormone, AtRALF1, is essential for processing. Overexpression of preproAtRALF1 causes semi-dwarfism whereas overexpression of preproAtRALF1(R69A), the propeptide with a mutation in the dibasic site, shows a normal phenotype. RALF1(R69A) plants accumulate only the mutated proprotein and not the processed peptide. In vitro processing using microsomal fractions suggests that processing is carried out by a kexin-like convertase.

Abbreviations: RALF, rapid alkalinization factor, MAP-kinase, mitogen-activated protein kinase, 35S, cauliflower mosaic virus 35S RNA promoter

Keywords: Convertase, Protein processing, Prohormone